Apparatus for coating cables



July 20, 1954 E J LARSEN E AL 2,684,050

APPARATUS FOR COATING CABLES Filed June 3, 1950 m J L lNl/EN Tom E J LARSE/V CW/QUTH A T TOR/V5 V Patented July 20, 1954 UNITED STATES PATENT GFFICE APPARATUS FOR COATING CABLES Elmer .J. Larsen, Parkville, and Charles W. Ruth, Baltimore, Md, .assignors-to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application June 3, 1950, Serial No. 155,966

(Cl. Ila-4:05)

Claims. 1

This inventionrelates .to app ratus for coatin cables, and more particularly to apparatus for coating insulated cables before a lead sheath is extruded. around the cable.

Telephone cables which are buried underground for transmitting telephone messages over long distances may include a cable core enclosed in an insulating jacket and an outer lead sheath to make the cable air-tight and moisture tight. Predetermined lengths-of such cables may be manufactured by passing the core through apparatus designed to extrude a jacket of insulating material around the core and then passing the insulated core continuously and directly through an apparatus designed to continuously extrude a lead sheath around an insulated core. It is desirable to coat the insulating jacket of the cable with a soft, plastic compound before the lead sheath is extruded around the jacket. l-Ieretofore, no satisfactory apparatus has been developed to apply a uniform coating around the jacket of a cable being advanced to and through lead sheath extruding apparatus.

An object of the invention is to provide new and improved apparatus for coating cables.

Another object of the invention is to provide new and improved apparatus for coating insulated cable cores being advanced to and through lead extruding apparatus.

An apparatus illustrating certain features of the invention for coating insulated cables may include a chamber for receiving a continuous supply of a coating compound and having entrance and exit openings through which a cable to be coated may be advanced, means for draining any excess compound from the chamber, and means communicating withthe chamber. through which the cable may pass for circulatin the coating compound from the exit .port thereof. in contact with the cable a predetermined distance and back to the draining means.

Other objects and advantages of the invention appear from the following detailed description of an apparatus forming a specific embodiment thereof, when read in conjunction with the appended drawings, in which:

Fig. l is an elevation of anapparatus embodying certain features of the invention for coating a cable core advancing to extruding apparatus;

Fig. 2 is a transverse section taken along line 2-2 of Fig. 1;

Fig. 3 is a transverse section taken along. line 33 of Fig. 1;

Fig. 4 is a transverse section taken along line 4-4 of Fig. 1, and

Fig. 5 is a transverse section taken along line 55 of Fig. 1.

Referring nowin detailtto the drawings, and more particularly to Fig. 1,. there is shown a coating unit ill for applying a coating ll of a suitable sealing compound around a cable advanced (by means not shown) to and through a lead extruding apparatus is designed to extrude a lead sheathlt around the coated core. The cable 13 includes a core it surrounded by an insulating jacket .26, which may be made of various insulating compounds such as rubber or rubber compounds, or various thermoplastic in-' sulating compounds such as polyethylene (polymereized ethylene).

The coating unit ill includes an outer tank 23 having entrance and exit openings E i and 25, respectively, th ough which the cable 53 may be advanced, and an opening 25 in the bottomthereof which communicates with a duct 23. A tank til, substantially smaller in length, width and height than the tank 23, is positioned in the tank 23 so that a space exists between the sides, bottom and one end of the tank 3t and the adjacent sides, end and bottom of the tank 23. The right hand end of the tank 39, as viewed in Fig. l is open and abuts an end plate Si of the outer tank 23 so that the exit opening 25 communicates with the tank it.

A liquid coating compound is supplied continuously to a trough 33 by a pipe 3 1 connected to a circulating pump and pipe system (not shown) and discharges from the trough 33 into the inner tank 30. The compound is supplied to the trough 33 at such a rate that the tank is maintained completely full of the compound, and the excess compound flows over the sides and ends of the tank so into the outer tank 23 and drains therefrom into the duct 23 which conveys the excess compound to a tank (not shown) in which a supply of the coating compound is maintained. A sliding door 35 may be moved upwardly manually to drain compound through an opening 36 provided in the inner tank St to empty the tank 36 into the tank 23 and thence into the duct 28 when it is desirable to drain the tank at. The entrance end of the tank 30 is provided with a wiping block 37, which may be made of rubber or other suitable resilient material, designed to fit neatly around the cable is and prevent any foreign substance which may be on the cable from entering the inner tank 36.

An elongated inner pi c it (Figs. 1 and 4) has a flange ll on one end thereof which is secured to the end plate 3! by bolts so that the pipe lil communicates with the exit 25 of the tank 36. An outer pipe l -l, larger in diameter than the pipe 49, is secured to the flange Ali concentrically with respect to the pipe in. The pipe M is somewhat shorter than the pipe ll and spacers d5 d5 equally spaced about the pipe 39 position the ends of the pipes All and 4d concentrically with respect to one another. The pipe lid is designed to fit neatly into an elongated tube 38 screwed into an annular core tube holder seated in the end of an elongated tubular barrel 5I forming part of the lead press I5. The pipes 40 and 44 are of such length that when the pipe 44 extends into the tube 48 a short distance, the free end of the inner pipe 40 is positioned close to an annular core tube 55 positioned on the end of the core tube holder 50. Spacers 53-53, similar to the spacers 4545, are mounted on and equally spaced about the pipe 40 and serve to align the pipe 40 concentrically within the tube 48. Spacers 53-53 (Fig. 5) equally spaced about the end of the pipe 40 position the pipe 45 concentrically with respect to the tube 48 of the lead press l5.

The core tube 55 (Fig. 1) coacts with an annular forming die 56 to form an extrusion orifice 51 in the lead press I5 through which molten lead 60 is forced by a rotating screw GI to form the lead sheath I5 around the coated, insulated core I3. The forming die 56 is fitted into an internal bore provided in a die holder 63 secured on the end of the extruding apparatus by a nut 54. The nut 64 is provided with internal threads to receive a bushing 65 which holds the forming die 56 firmly in place in the die holder.

The lead press i5 (Fig. 1) may be of the type generally known as a Pirelli lead press, which is described fully on pages 310 to 423, inclusive, of the issue of the British publication Engineering published April 8, 1949, and the lead press I5 has been described only insofar as it is necessary for a complete understanding of the invention.

The sealing compound supplied to the inner tank 3!] (Fig. 1) flows through the inner pipe 48 and thereby surrounds the cable l3 being advanced through the tank 33 and the pipe 40 to the lead extruding apparatus I5. The sealing compound discharges from the end of the pipe 48 and fills the annular clearance between the cable l3 and the core tube 55, between the pipe 49 and tube 48 and between the pipes 40 and 44. The compound flows from the annular clearance between the pipe 40 and the tube 43 through the pipe 44 and through an opening 48 (Figs. 1 and 4) provided in the flange M at the bottom of the pipe 48 into the outer tank 23, and thence into the duct 28. The viscosity of the coating compound and the size of the opening regulate the circulation of the compound through the pipes 40 and 44 so that the compound fills the space between the pipe at and the tube 43, and between the pipes at and it to the level of the compound in the tank 36. As the cable I3 advances through the tank 33 and the pipe 43, a coating of the compound adheres to the jacket 2b in a more or less irregular or uneven thickness. As the cable passes through the central opening of the core tube 55, the opening in the core tube smooths out the compound adhering to the jacket into a uniform and concentric coating I I. As the coated cable emerges from the die the lead 56 is extruded therearound to form the sheath IS.

The coating compound is supplied continuously to the tank 30 of the coating unit it at a rate sufficient to keep the cable surrounded thereby throughout its travel from the wiping block 31 to the central opening of the core tube 55 in order to obtain an even coating II on the cable I3. If the cable was not surrounded with coating compound until it passed through the core tube, the compound on the cable would flow to the bottom of the cable. As a result, the core tube would wipe off the excess compound on the bottom of the cable and leave an uneven coating on the cable.

The barrel 5!, the tube 48, the core tube holder 50 and the core tube 55 are maintained at a temperature sufiicient to keep the lead 60 at an extrudable temperature. The coating compound may be of the type which must be heated so that it can be readily circulated through the coating unit it. The coating compound is circulated from the tank 30 into the lead press I5 and from the lead press into the tank 23 and duct 28 at a sufficient rate of flow to prevent charring of the compound on the core tube 55 and the elongated tube 48.

Operation The cable I3 is advanced continuously at a predetermined rate from a supply reel or directly from apparatus which extrudes the insulating jacket 20 on the core I8, and passes through the entrance opening 24 of the tank 23, the tank 30, the pipe 4! and the extrusion orifice 51 of the lead press I5. A suitable sealing compound, from which the coating 1 I is formed, is supplied to the trough and discharged therefrom into the tank 3th at such a rate that it completely fills the tank 30 and circulates from the exit port 25 along the cable through the pipe 49 into the annular clearance between the pipe 49 and the elongated tube 48, and the annular clearance between the cable I3 and the core tube holder 50 and the core tube 55 of the lead press I5. The compound flows through the tube 48 and the pipe 44 into the outer tank 23 from which it flows into the duct 28 and returns to a supply tank (not shown) for the sealing compound.

As the cable enters the inner tank 30, the wiping block 31 cleans the surface of the jacket 20 so that any foreign substance on the jacket is removed before the cable enters the tank 30. The sealing compound in the tank 30 and in the pipe 46 surrounds the cable I3 completely, and the compound adheres to the jacket 23 of the cable. ihe movement of the cable I3 through the tank 36 serves to siphon the sealing compound from the tank into the pipe 48, whereby a substantial quantity of the compound discharges into the annular clearance between the cable I3 and the core tube holder 50 and the core tube 55. The compound piles up at the core tube 55, and as the cable I3 passes through the annular opening in the core tube, the core tube smooths the compound uniformly and concentrically on the cable. As the coated cable enters the extrusion orifice 51, the screw 6| extrudes the molten lead 69 into the form of a lead sheath I6 around the coated cable. This arrangement produces a substantially uniform coating II of compound between the jacket 20 and the lead sheath I6.

While the above-described apparatus is designed to coat a cable being advanced to a lead press, it may be readily modified to suit various types of filamentary articles and associated manufacturing apparatus without departing from the spirit and scope of the invention.

What is claimed is:

1. In a cable core covering apparatus including an elongated, tubular barrel through which a cable core to be covered may be advanced and a die at the exit end of said barrel for formin a sheath on the cable core, the improved applicator for applying liquid coating compound to the core which comprises a receptacle for receiving a continuous supply of liquid coating compound and having aligned entrance and exit ports through which the cable core is advanced, an inner elongated tube projecting from the receptacle in alignment with said ports so as to surround the advancing cable core, said tube being designed to extend into the tubular barrel to a point adjacent to the die at the exit end of the barrel, a larger outer tube having one end thereof surrounding the initial portion of the inner tube which is positioned in said barrel, whereby liquid coating compound flows from the receptacle through the inner tube around the advancing cable core until the core reaches a point near the die and the excess coating compound flows out of the barrel in the opposite direction around the inner tube and through the outer tube, and means at the other end of the outer tube for conducting away the excess coating compound.

2. In a cab e core covering apparatu including an elongated, tubular barrel through which a cable core to be covered may be advanced and a die at the exit end of said barrel for formin a sheath on the cable core, the improved applicator for applying liquid coating compound to the core which comprises a receptacle for receiving a continuous supply or liquid coating compound and having aligned entrance and exit ports through which th cable core is advanced, an inner elongate; tube projecting from the receptacle in alignment with said ports so as to surround the advancing cable core, said tube being designed to extend into the tubular barrel to a point adjacent to the die at the exit end or" the barrel, a plurality of spacers for supporting said tube concentrically within the tubular barrel, a larger outer tube having one end thereof surrounding the initial portion of the inner tube which is positioned in said barrel, said outer tube fitting closely within said barrel so as to prevent a leakage of liquid coating compound therebetween, whereby liquid coating compound flows from the receptacle through the inner tube around the advancing cable core until the core reaches a point near the die and the excess coating compound fiows out of the barrel in the opposite direction around the inner tube and through the outer tube, and means communicating with the other end of the outer tube for conducting away the excess coating compound.

In a cable core covering apparatus including an elongated, tubular barrel through which a cable core to be covered may be advanced and a die at the exit end of said barrel for forming a sheath on the cable core, the improved applicator for applying liquid coating compound to the core which comprises a receptacle for receiving a continuous supply of liquid coating compound and having aligned entrance and exit ports through which the cable core is advanced, wiping means positioned adjacent to the entrance port in the receptacle for conditioning the surface of cable core prior to the application of the liquid coating compound, an inner elongated tube projecting the receptacle in alignment with said ports so as to surround the advancing cable core, said tube being designed to extend into the tubular barrel to a point adjacent to the die at the exit end 0}: the barrel, a larger outer tube having one end thereof surrounding the initial portion of the inner tube which is positioned in said barrel, whereby liquid coating compound flows from the receptacle through the inner tube around the advancing cable core until the core reaches a point near the die and the excess coating compound flows out of the barrel in the opposite direction around the inner tube and through the outer tube, and means external of the barrel communicating with the other end of the outer tube for conducting away the excess coating compound.

4. In a cable core covering apparatus including an elongated, tubular barrel through which a cable core to be covered may be advanced and a die at the exit end of said barrel for forming a lead sheath on the cable core, the improved applicator for applying liquid coating compound to the core which comprises a receptacle for receiving a continuous supply of liquid coating compound and having aligned entrance and exit ports through which the cable core is advanced, an inner elongated tube projecting from the receptacle in alignment with said ports so as to surround the advancing cable core, said tube being designed to extend into the tubular barrel to point adjacent to the die at the exit end of the barrel, a larger outer tube surrounding the initial portion of the inner tube which is positioned in said barrel, said outer tube fitting closely within said barrel so as to prevent a leakage of liquid coating compound therebetween, whereby liquid coating compound will fiow from the receptacle through the inner tube around the advancing cable core until the core reaches a point near the die and the excess coating compound flows out of the barrel in the opposite direction around the inner tube and through the outer tube, and a drain positioned adjacent to the receptacle for receiving any coating compound overflowing the sides of the receptacle and communicating with the outer tube so as to drain the excess coating compound therefrom.

5. In a cable core covering apparatus including an elongated, tubular barrel through which a cable core to be covered may be advanced and a die at the exit end of said barrel for forming a sheath on the cable core, the improved applicator for applying liquid coating compound to the core which comprises a receptacle for receiving a continuous supply of liquid coatin compound and having aligned entrance and exit ports through which the cable core is advanced, an inner elongated tube projecting from the receptacle in alignment with said ports so as to surround the advancing cable core, said tube being designed to extend into the tubular barrel to a point adjacent to the die at the exit end of the barrel, a plurality of spacers for supporting said tube concentrically within the tubular barrel, 2, larger outer tube having one end thereoi surrounding the initial portion of the inner tube which is positioned in said barrel, said outer tube fitting closely within said barrel so as to prevent a leakage of liquid coating compound therebetween, a second plurality of spacers for supporting the inner tube concentrically within the outer tube, whereby liquid coating compound flows from the receptacle through the inner tube around the advancing cable core until the core reaches a point near the die and the excess coating compound flows out of the barrel in the opposite direction around the irmer tube and through the outer tube, and means communicating with the other end of said outer tube for conducting away the excess coating compound.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 515,951 Cobb Mar. 6, 1894 1,605,326 Bundy Nov. 2, 1926 1,682,823 Barord Sept. 4, 1923 2,287,825 Postlewaite June 30, 1942 2,301,165 Neal Nov. 3, 1942 2,390,823 Bennett Dec. 11, 1945 2,461,647 Lovett et a1 Feb. 15, 19%9 

